On Fri, Oct 12, 2018 at 06:55:48PM +0200, Michal Hocko wrote:

On Fri 12-10-18 12:09:53, jglisse@redhat.com wrote:

...

From: Jérôme Glisse jglisse@redhat.com

Inside set_pmd_migration_entry() we are holding page table locks and thus we can not sleep so we can not call invalidate_range_start/end()

So remove call to mmu_notifier_invalidate_range_start/end() and add call to mmu_notifier_invalidate_range(). Note that we are already calling mmu_notifier_invalidate_range_start/end() inside the function calling set_pmd_migration_entry() (see try_to_unmap_one()).

Signed-off-by: Jérôme Glisse jglisse@redhat.com Reported-by: Andrea Arcangeli aarcange@redhat.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Zi Yan zi.yan@cs.rutgers.edu Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Anshuman Khandual khandual@linux.vnet.ibm.com Cc: Dave Hansen dave.hansen@intel.com Cc: David Nellans dnellans@nvidia.com Cc: Ingo Molnar mingo@elte.hu Cc: Mel Gorman mgorman@techsingularity.net Cc: Minchan Kim minchan@kernel.org Cc: Naoya Horiguchi n-horiguchi@ah.jp.nec.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Vlastimil Babka vbabka@suse.cz Cc: Michal Hocko mhocko@kernel.org Cc: Andrea Arcangeli aarcange@redhat.com

Is this worth backporting to stable trees?

Yes it is i forgot to cc stable :(

The patch looks good to me Acked-by: Michal Hocko mhocko@suse.com

...

---

mm/huge_memory.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 533f9b00147d..93cb80fe12cb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2885,9 +2885,6 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, if (!(pvmw->pmd && !pvmw->pte)) return;

• mmu_notifier_invalidate_range_start(mm, address,

• 	address + HPAGE_PMD_SIZE);
  

• flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); pmdval = *pvmw->pmd; pmdp_invalidate(vma, address, pvmw->pmd);

@@ -2898,11 +2895,9 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, if (pmd_soft_dirty(pmdval)) pmdswp = pmd_swp_mksoft_dirty(pmdswp); set_pmd_at(mm, address, pvmw->pmd, pmdswp);

• mmu_notifier_invalidate_range(mm, address, address + HPAGE_PMD_SIZE); page_remove_rmap(page, true); put_page(page);

• mmu_notifier_invalidate_range_end(mm, address,

• 	address + HPAGE_PMD_SIZE);
  

} void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) -- 2.17.2

-- Michal Hocko SUSE Labs